Production of butinediol



Patented Nov. 1, 1949 Thomas E. Londergan,

Niagara Falls, N. Y., as-

signor to E. I. du Pont de Nemours & Company, Wilmington, Del., acorporation of Delaware No Drawing.s

Application October 4, 1947, erial No. 778,023

2 Claims. (CL 260-635) This invention relates to an improved process forthe production of 2-butinediol-1,4.

The recently granted patent to Reppe et al., I). 8. Patent No.2,232,867, discloses a process for the production of 2-butinediol-1,4 byreacting an aqueous solution of formaldehyde with acetylene in thepresence of a metal acetylide catalyst selected from the groupconsisting of copper acetylide, silver acetylide, gold acetylide, andmercury acetylide. By the process of said patent, it is impossible toobtain a satisfactory yield of the butinediol within a reasonable periodof time unless the process is operated at super-atmospheric pressure. Onthe other hand, when super-atmospheric pressures are used, as suggestedin the patent, the process is dangerous by reason of the explosionhazard of acetylene under pressure. The process of the above-said patentis also subject to the objection that the 2-butinediol-1,4 producedcontains, as an impurity, small amounts of propargyl alcohol.

It is an object of this invention to provide a process for theproduction of 2-butinediol-1,4 which will have an excellent yield andmay be carried out in a minimum period of time at atmospheric pressure.

It is another object of this invention to provide a process for theproduction of 2-butinediol-1,4 which will have an excellent yield andmay be carried out in a minimum periodof time without objectionableexplosion hazard.

It is another object of this invention to provide a process for theproduction of 2-butinediol- 1,4 which is substantially free frompropargyl alcohol.

Other objects of the invention will appear hereinafter.

The objects of this invention may be accomplished, in general, byreacting a polyoxymethylene glycol containing between eight and onehundred formaldehyde units per molecule with acetylene in diethyleneglycol diethyl ether containing not to exceed 5% free water. tion iscarried out in the presence of a metal acetylide taken from the groupconsisting of copper acetylide, silver acetylide, gold acetylide, andmercury acetylide, and at a temperature between 60 C. and 150 C.

The above-said polyoxymethylene glycol includes paraiormaldehyde, whichStaudinger has defined as a mixture of polyoxymethylene glycolscontaining between eight and one hundred formaldehyde units, as well assimilar polymers of formaldehyde which may have a more uniform degree ofpolymerization. It has been found, in accordance with this invention,that commercial The reacformaldehyde solutions or similar aqueoussolutions of formaldehyde cannot be reacted with acetylene atatmospheric pressure to produce a good yield of the butinediol unlessthe reaction 5 is carried out for a long period of time (a period of twoor more days). By the use of paraformaldehyde, or similarpolyoxymethylene glycol, in diethylene glycol diethylether containingnot to exceed 5% free water, a good yield can be ob tained atatmospheric pressure in a period of two to six hours. Not only is theparaformaldehyde more reactive than formaldehyde but free water inlarger quantities than about 5%, as well as alcohol and hydrocarbons, inthe reaction medium have a decided inhibiting effect on the re action.On the other hand, it has been found that polyoxymethylene glycolshaving more than one hundred formaldehyde units per molecule, 1. e.,formaldehyde polymers known as alphapolyoxymethylene, are not suitablefor the production of 2-butinediol-1,4 since they are not sufficientlyreactive.

Paraformaldehyde is readily produced by the evaporation of aformaldehyde solution, and the as process of this invention may becarried out with paraformaldehyde produced in situ in the reactionmedium by passing an aqueous formaldehyde solution into the hot reactionmedium through which an excess of acetylene is being swept so as tocarry off excess water. This procedure must be so controlled that aconcentration of more than 5% free water will never be present in thereaction mixture. Paraformaldehyde can also be produced in situ bypassing formaldehyde gas into a substantially non-aqueous reactionmixture. Aqueous formaldehyde solutions such as commonly marketed, ormonomeric formaldehyde gas, as such, are not satisfactory for use incarrying out the present invention.

Acetylene usually contains a considerable proportion of water. It may,therefore, be necessary to first dry the acetylene before passing thesame into the reaction mixture to prevent building up a concentration ofmore than 5% free water.

In accordance with the present invention, the reaction between theacetylene and the polyoxymethylene glycol is carried out in diethyleneglycol diethyl ether. As above stated, water, alcohol, and hydrocarbonshave now been found to inhibit the reaction. The diethylene glycoldiethyl ether reaction medium employed must, therefore, contain lessthan 5% free water or like reaction-inhibiting liquid. The amount of thediethylene glycol diethyl ether employed is not critical. A sufficientamount should, of course, be used to maintain the reaction mass in aliquid,

dissolved or slurry, form. In a batch type process, the diethyleneglycol diethyl ether is preferably employed in an amount between threeand twenty times the weight of the polyoxymethylene glycol present inthe reaction mass. In a continuous type process, the butinediol may becontinuously removed by distillation of the reaction mass, and thediethylene glycol diethyl ether recycled. The 2-butinediol-L4 producedby the reaction will, unless removed, accumulate in the reaction mass.It has now been found that small amounts of'the butinediol will notinterfere with the reaction; however, if it is allowed to accumulateuntil it exceeds about 50%, based on the combined weight of thebutinediol and the diethylene glycol diethyl ether, it will materiallyinterfere with the production of good yields. It is, therefore,preferred that the concentration of the butinediol product in thereaction mass be not allowed to exceed 50%, based on the combined weightof the butinediol and the diethylene glycol diethyl ether. This may bereadily accomplished by discontinuing the reaction or by addingadditional diethylene glycol diethyl ether in a batch type process, orby continuous removal of the butinediol from the reaction medium bydistillation of the reaction mass and recycling of the diethylene glycoldiethyl ether, or by continuous addition of diethylene glycol diethylether in a continuous type process.

The metal acetylide catalyst, i. e., copper acetylide, silver acetylide,gold acetylide, or mercury acetylide, or any mixture or combinationthereof, may be prepared from aqueous metal salt solutions as disclosedin the above-said patent to Reppe et al. The metal acetylide should becontained on a catalyst support such as fullers earth, infusorial earth,activated carbon silica gel, or the like. The preferred metal acetylidecatalyst material for use in accordance with this invention is oneproduced by mixing particles of a catalyst support having a size not toexceed 300-mesh with an aqueous solution of a metal salt, andprecipitating the metal acetylide on the particles of catalyst supportby passing acetylene through the said mixture. precipitated on theparticles of support should not exceed 20%, by weight, of the final drycatalyst. This particular catalyst and the method of producing the sameis the subject of my 00- pending patent application Serial No. 561,150,filed October 30, 1944, and now abandoned. The amount of catalystpresent in the reaction mass may be varied between wide limits, forexample, the presence of 1% to based on the weight of thepolyoxymethylene glycol present, will catalyze the reaction.

The reaction between the polyoxymethylene glycol and the acetylene willtake place at atmospheric pressure at any temperature between C. and 150C. In order that good commercial yields be obtained in minimum time andin order to maintain the process under safe conditions of operation, itis preferred to carry out the reaction at a temperature between C. andC.

The following detailed examples are given to illustrate certainpreferred methods for carrying out the present invention, it beingunderstood, of course, that the precise details set forth in theseexamples are to be taken as illustrative and not limitative of theinvention.

Example I A suspension of a catalyst, composed of six grams of copperacetylide on 30 grams, 300-mesh 0r flner substantially pure, neutralactivated car- The quantity of metal acetylide bon, in 250 cc. ofdiethylene glycol diethyl ether was placed in a one-liter flask andheated to between 115 C. and 120 C. To this mixture was added 31.5 gramsof paraformaldehyde, and dry acetylene was passed into the flask withagitation. The acetylene was passed into the flask at the rate at whichthe acetylene was substantially completely absorbed and the rate ofabsorption was noted. More paraformaldehyde was added as needed. Whenabout two mols of paraformaldehyde had reacted, the reaction mixture wascooled, filtered and distilled by vacuum distillation, distilling at 120C. to 145 C. at 7 mm., to isolate the 2-butinediol-l,4 formed in thereaction. On redistillation, substantially pure 2-butinediol-L4, boilingat C. to C. at 7 mm., was secured.

A yield of about 79% of the theoretical yield was obtained. Thebutinediol produced by the above reaction was free from propargylalcohol.

Example II Two mols of formaldehyde in the form of 60 grams falpha-polyoxymethylene containing 99.9% of formaldehyde were added to400 grams of diethylene glycol diethyl ether containin 16 grams ofcopper acetylide on 80 grams of powdered, substantially pure, neutralactivated carbon. Acetylene was passed through the resultant mixturewith agitation for one hour at 100 C. with absorption of only 2.5liters; the temperature was then raised to 125 C. but only 1.3 literswere absorbed in one-half hour. This is only 25% to 27% of the quantityof acetylene which would be absorbed by paraformaldehyde under similarcircumstances. This example illustrates that alphapolyoxymethylene isnot sufliciently reactive to be a satisfactory reactant for use inaccordance with the present invention.

Example III An approximately equimolar mixture of acetylene andmonomeric formaldehyde gas containing about one mol each of formaldehydeand acetylene was bubbled through 300 grams of diethylene glycoldiethylether, containing eight grams of copper acetylide on 40 grams ofsubstantially pure, neutral activated carbon, with agitation at 100 C.in the course of two and onequarter hours. In this time, only about 13%of the acetylene was absorbed, indicating that only 25% of thetheoretical quantity had reacted. At the same time, all of theformaldehyde was absorbed and held by the reaction mixture. Acetylenewas then passed through the mixture for four and one-quarter hours inwhich time about 65% of the theoretical amount reacted, making a totalof 90% theoretical for one mol formaldehyde.

These results indicate that during the first two and one-quarter hours,about 75% of the 1 formaldehyde either polymerized or formed a plosionsuch as is present in the handling or maintaining of the acetylene atpressures above atmospheric. The reaction takes place rapidly withexcellent yields without the production of prropargyl alcohol, and thebutinediol can be readily isolated from the solvents employed since itis substantially free from water.

Throughout the specification and claims, proportions and percentagesrefer to proportions and percentages by weight unless otherwisespecifled.

Since it is obvious that many changes and modifications can be made inthe above-described details without departing from the nature and spiritof the invention, it is to be understood that the invention is not to belimited to a the above-said details except as set forth in the appendedclaims.

What is claimed is:

1. A process for the production of 2-butinedim-1,4 which comprisesreacting, at a temperature between 60 C. and 150 C., a polyoxymethyleneglycol containing between eight and one hundred formaldehyde units permolecule with acetylene in diethylene glycol diethyl ether which doesnot contain to exceed 5% by weight of free water and which is present insumcient amount to maintain the reaction mass in liquid form, saidreaction being carried out in the presence of a metal acetylide catalysttaken from the group consisting of copper acetylide, silver acetylide,gold acetylide, and mercury acetylide.

2. A process for the production of 2-butinediol-l,4 which comprisesreacting, at a temperature between C. and C'., a polyoxymethylene glycolcontaining between eight and one hundred formaldehyde units per moleculewith acetylene in diethylene glycol diethyl ether which does not containto exceed 5% by weight of free water and which is present in suillcientamount to maintain the reaction mass in liquid form, said reaction beingcarried out in the presence of a metal acetylide catalyst taken from thegroup consisting of copper acetylide, silver acetylide, gold acetylide,and mercury acetylide. I

THOMAS E. LONDERGAN.

REFERENCES CITED The following referencesare of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,106,181 Kreimeier Jan. 25, 19382,232,867 Reppe et al. Feb. 25, 1941 2,250,445 Bruson et al. July 29,1941

